Vaisala Transmissometer LT31


The world’s best, most accurate, and most frequently used visibility measurement instrument for runway visual range.

Cutting-Edge Visibility Technology

Transmissometer technology provides today’s best visibility measurement accuracy for Runway Visual Range (RVR), and Vaisala’s LT31 is the most trusted and frequently used transmissometer the world over. By measuring light attenuation (reduction in light) between the transmitter and receiver, the LT31 is thus independent of the type of visibility reducing particles present — ensuring the best accuracy in the most crucial low-visibility situations, and in all conditions. It automates many critical functions to provide unmatched accuracy, outstanding uptime, and minimal maintenance needs — ensuring the safety and efficiency of your airport operations.

Compliant & Cost-Effective

With LT31, airports have the necessary information to ensure safety of runway operations while maximizing capacity during all types of weather. Other benefits include:

  • Simplified compliance — Meet ICAO requirements and national and local certifications for CAT I to CAT III airports.
  • Fail-safe operation: Transmissometers report lower-than-actual visibility if there is a disturbance to the measurement.
  • Low maintenance costs: Extensive self-diagnostics, ruggedness, and automation mean maximum uptime and minimized maintenance.

Features At A Glance

The features that make the LT31 transmissometer the gold standard:

  • Vaisala-patented automatic calibration
  • Automatic alignment
  • Intelligent contamination avoidance and compensation
  • Meteorological Optical Range (MOR) of 10km
  • Full compliance with ICAO and WMO requirements
  • White LED light source
  • Straightforward maintenance
  • Optional present weather reporting